In general, a dash panel is mounted at the boundary between an engine room and the interior of a vehicle and a dash pad that absorbs and blocks engine noise transmitted to the interior is mounted on the dash panel.
The dash pad blocks, removes, and absorbs engine noise and prevents high/low-frequency complex energy, which is generated in driving, from being transmitted to the interior of a vehicle.
Dash pads for a vehicle in the related art have structures formed by stacking different materials having different thicknesses and weight for the types of vehicles, as listed in the following Table 1.
TABLE 1ItemExisting dash pad (Arrangement: Sound-absorbing layer -> Sound-blocking layer)1PU(85K) + PA6 film (50 g) + TPE (2.5 t) + PET (1,000 g) [or Modified cross-section fiber (1,000 g)]: Large-size car    PA6 film: To bond an sound-absorbing layer and a sound-blocking layer (functioning as an adhesive)2PU(85K) + PA6 film (50 g) + Hard PET(1,000 g): Small-sized car, gasolinePU(85K) + H/Layer (1.5 t) + Hard PET(1,000 g): Small-sized car, diesel3PU(85K) + PA6 film (50 g) + Hard PET(800 g): RV gasolinePU(85K) + EVA(2.0 t) + Hard PET(800 g): RV diesel4Soft PET + Hard PET
The dash pads listed in Table 1, as illustrated in FIGS. 1A-1D, have a stacking structure of two to four layers from a sound-absorbing layer (engine room) to a sound-blocking layer (interior).
As described above, although the existing dash pads are manufactured in the structures formed by stacking different materials in two to four layers for the types of vehicles in order to improve sound-absorbing/blocking performance, PU material is generally used for the sound-absorbing layer and hard PET is generally stacked for the sound-blocking layer, so the weight and manufacturing costs are generally increased.
There is a need of a mold, a trimming mold, and a PU foaming mold for producing actual products, including a start mold and a mass production mold for examining performance in mass production, so the investment cost and manufacturing cost are increased. Further, there is a need of a film (PA6) for bonding the sound-absorbing layer and the sound-blocking layer, so the manufacturing cost and the number of processes are increased.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may include information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.